Pressure switches are a part of our lives, but many people might not even know they exist. They are vital pieces of equipment to ensure the things we rely on work, like smartphones, aeroplanes, irrigation systems and energy systems. But what are pressure switches and how are they implemented in our everyday objects?
What is a pressure switch?
A pressure switch, sometimes called a pressure sensor, provides electrical feedback on the rising or falling pressure within a chamber. When the pressure meets a predetermined level, the pressure switch will engage to relieve or build up the pressure.
Let’s take a look at where you can find pressure switches.
Well water pumps
Well water, or borehole, pumps are submersible pumps used for the spraying, pumping and irrigation of stored water from water butts. The pressure switch signals to the well pump whether to start or stop pumping depending on the pressure in the water system.
A bad well pressure pump can result in low water pressure or possibly no water at all coming from the system. Your well water pump pressure switch might also be failing if it continually cycles for no apparent reason.
Electronic gas compressors
In the energy sector, a gas compressor is an essential piece of equipment. They are used in the production of electricity and heat production plus hydrocarbon extraction. The correct gas pressure is vital for the transportation of gas through pipelines and the lifting of oil in gas-lift operations.
Pressure switches are important for keeping the pressure at a consistent level; too much and the gas could change phase into a liquid. Alternatively, this may be the desired effect, in which case it’s important to ensure that transformation can be completed.
In-cell charge control inside a battery
Battery charging is essential for renewable energy and without a pressure switch, there is a danger of overcharging. However, pressure switches built into a battery cell disconnect the charging current whenever the internal pressure reaches a certain limit.
This is essential for prolonging the life of a battery cell in things like cars and smartphones. Too much charging reduces the lifecycle and capacity of the battery while also corroding essential components.
Activating an alarm if aircraft cabin pressure drops
The pressure of an aircraft cabin must be maintained at the right level for the safety of everyone on board. If the air pressure is too low at high altitudes it means your body isn’t receiving enough oxygen, triggering confusion, sleepiness or hypoxia (a lack of oxygen).
Cabin pressure is maintained via an outflow valve which ensures the incoming air remains in the cabin and is released at the correct rate. The use of a pressure switch for activating an alarm if cabin pressure drops is essential for maintaining safety at all times. If pressure is lost, oxygen masks are deployed to ensure everyone is getting enough but this could not happen without a working pressure switch.
Pressure panels on sliding doors
Sliding doors work in several ways but some use pressure panels to detect when someone is trying to walk through them. Once the pressure panel senses a change, thanks to the added force of someone stepping on it, the sliding door is activated and it opens up.
Needless to say, if the pressure switch on a sliding door pressure panel isn’t working, the door won’t open. Instead, it will have to be manually opened, which isn’t always easy or possible. There is also a risk that unsuspecting people could walk into the door expecting it to open as normal.
Powering refrigeration units
High and low-pressure switches are used as protective devices for compressor and refrigeration circuits. Refrigerants work by bringing hot gas into a compressor where it is subjected to high pressures.
The high pressure forced upon the gas turns the vapour into a liquid that absorbs heat from the conversion process. This is then passed into a low-pressure environment which forces the refrigerant to cool back to liquid form.
That exchange of heat causes evaporation which places a cooling load into the refrigerator. Gas is once again absorbed by the refrigeration unit, starting the cycle over again. Ensuring the pressure is maintained through a switch at both high and low ends allows the refrigeration process to continue working effectively.
Our pressure switch products
Here at Applications Engineering, we supply a variety of pressure switches for use in a variety of industries. Our pressure switches can be used in a variety of different areas including oil, air, water, compressors and differentials.
We are also specialists in high-quality fire sprinkler valve systems that are fit for purpose in modern domestic and residential properties. We supply to a huge range of companies and businesses, so get in touch to discover which pressure switch is best suited to your needs.
Filed under: Advice and Information